Project Nissan 350Z Part 2 – Installing KW Clubsport Suspension and Whiteline Sway Bars

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We told Sera to do something cute and we think she took offense to that.

A really cool feature that the Clubsports have is the remote accumulator.  The accumulator is like a remote reservoir found in some super high end race shocks.  On the Clubsports this accumulator is a canister with a rubber bladder that is pressurized with nitrogen gas. Oil from the outer tube can flow back and forth from the outer tube to the accumulator.  The bladder inside the accumulator gives the fluid displaced by the volume of the shock shaft as it goes in and out of the shock body a place to go.  The rubber flexes and the gas compresses giving the incompressible fluid room, preventing the shock from getting hydraulic lock.

The rear shocks reuse the stock upper mount.

Typically, a twin tube shock simply has a volume of air or gas in the outer tube at the top of the fluid to allow for shaft displacement.  This works OK, but under hard use the air can get mixed with the fluid and the frothy mix has less damping than non-emulsified fluid.  This mixing of air and oil is the primary cause of shock fade in hard use.  Another disadvantage of a standard twin tube is that usually only a low gas pressure can be used if indeed the shock is even gas pressurized.  Pressurization is good because it reduces fluid cavitation through the valves at high piston speeds.  Cavitation is localized boiling in low pressure zones like the backside of shock valves.  Cavitation also causes the fluid to foam and lose damping ability. The Clubsport's accumulator and rubber bladder prevent the gas and fluid from mixing.  The bladder is pressurized to about 60 psi with nitrogen gas to reduce cavitation of the fluid.

To convert the rear springs to a height adjustable coilover spring, we had to drill a hole in the rear lower control arm to mount the spring seat.

The KW’s have a shorter shock body so the car can be lowered without giving up wheel travel. Bottoming under roll when cornering is the #1 cause of ill handling in modified cars so it's critical not to give up bump travel in a lowered car.  We adjusted our Z about 1.2 inches lower in the front and 1 inch lower in the rear for now and might lower it some more once we decide what wheel and tire combination we are going to run.

Here is the hole as seen from the bottom.

KW addresses some of the issues that coilovers usually have on street cars.  Many times the threaded body of the shock corrodes as it’s hard to keep cut threads from rusting, especially where the spring collars are turned on the threads even with rust resisting platings and coatings.  Typically the spring seat is made of a different metal than the shock body.  This causes galvanic corrosion. The shocks on a street car are exposed to the elements and receive very little maintenance.  These issues cause the threaded body to corrode to the spring seat making a frozen mess. KW addresses this issue by using their Inox stainless steel for the shock body.  The spring seat is made of a corrosion proof engineering super plastic.  This makes for a coilover body that that is always silky smooth in adjustment and will never corrode, even in salty east coast winters!  The main difference between Clubsports and KW 2-Way Motorsports shocks is that the Clubsports uses stainless bodies while the Two-Way Motorsports shocks use a zinc plated steel body.  Since steel has about twice the thermal conductivity of stainless, the Motorsports race shocks use the steel body to run cooler.